Multiple circuit control apparatus



Jan. 23, 1951 l. E. M cABE 2,539,259 MULTIPLE CIRCUIT CONTROL APPARATUS Filed April 29, 1947 2 sheets sheet 1 INVENTOR.

IRA E. M CJBE I. E. M CABE IULTIPLE CIRCUIT CONTROL APPARATUS Filed April 29; 1947 Jan. 23, 1951 2 sheets-sheet 2 IRA EM CABE Patented Jan. 3, 1951 a UNITED STATES PATENT OFFIC MULTIPLE cmeuffigilm. ArrAnA'rus Q In E. McCabe, Chicago, Ill. Application April 29, 1947, sci-a1 No. 144,043

Claims The invention relates to an electric control system and has reference more particularly to an improved control system of this character which will automatically control electric circuits in such devices as refrigerators, oil burners and the like 5 1947, entitled Multiple Contact Switch Structure and wherein the magnetic means for actuating the switch contacts are combined with one or more automatic condition responsive devices for selectively operating said magnetic means for csthe invention may consist of certain novel features of construction and operation as will be more fully described and particularly pointed out in the specification, drawings and claims appended hereto.

In the drawings, which illustrate an embodiment of the invention, and wherein like referenc'e characters are used to designate like parts- Figure 1 is a longitudinal sectional View through the glass container of a mercury switch of the type suitable for use in the present control apparatus;

Figure 2 is a longitudinal sectional view of the mercury switch of Figure 1 showing the switch contacts in elevation and in combination with magnetic actuating means;

Figure 3 is a plan view of the flexible hinge A member for supporting and resiliently biasing the tablishing a desired sequence in the operation 01' 2 the switch contacts.

Another object is to provide an electric control system including mercury switch .structure of the character described and wherein the switch contacts will coact and be responsive to magnetic means operated in response to certain conditions for providing energization of both starting and running windings of an electric motor, whereby to eiTect interruption of the starting winding after the motor is up to speed and opening of the motor circuit in case the motor is stalled or overloaded and for also preventing thereafter a restart of the motor, until following a time delay, both starting and winding circuits are again s1 multaneously closed.

A still further object is to provide an electric control system having application to electric circuits in addition to that as described above, as, for example, in oil burner control apparatus for simplifying said apparatus in providing control of an oil burner motor and electric ignition means associated therewith. The improved control system of the invention may be advantageously used to provide burner motor and ignition energization with subsequent cut-oil? of the ignition means and may be made functionally operative to prevent operation of'the burner motor without .a closure of the ignition circuit when starting the burner after a period of idleness.

With these and various other objects in view,

movable contacts of the mercury switch;

Figure 4 is a side elevational view of the hinge member shown in Figure 3;

Figure 5 is a schematic diagram of an electric circuit showing the mercury switch of Figures 1 and 2 in electric connection with the starting and running windings of an electric motor for illustrating the control system of the invention;

Figure 6 is a schematic circuit diagram similar to Figure 5 but illustrating the position of the parts during normal running of the motor;

Figure 7 is another similar diagram illustrating the position of the parts in the event of an overload condition on the motor;

Figure 8 is still another circuit diagram similar to Figure 5 but showing the position of the parts following opening of the switch circuits as a result of an overload condition;

Figure 9 is a schematic circuit wiring diagram of the control system of the invention as shown in Figure 5 but illustrating a form of latch mechanism in combination with an eiectrothermal actuator for controlling the magnetic means of the switch;

Figure 10 is a circuit diagram similar to Figure 9 illustrating the position of the actuator and the latch mechanism in the event of an overload on the motor;

Figure 11 is a schematic diagram showing the mercury switch and magnetic actuating means of Figure 2 in combination with a temperature responsive device for controlling operation of both magnetic means and a second condition responsive device for controlling operation of only one of said magnetic means; and

Figure 12 is still another schematic circuit diaoocram illustrating the control system of the inv a small body of mercury or other electrical conducting fluid II which has electrical connection with the contact I2. The opposite end of the tube I is suitably closed, the said end having sealed therein one or more lead-in wires I3 and I4, which wires may have connection with individual circuits, the same being selectively controlled with respect to contact I2 by means of a plurality of movable electrodes or contact members I and I1.

The movable electrode I5 is provided with a contact point It for making and breaking its respective electric circuit with respect to the pool of mercury II. The movable electrode I1 is likewise provided with a contact point I8 which also has coaction with the mercury pool for making and breaking the electrical circuit connecting therewith. The electrodes I5 and H are supported from the lead-in wires I3 and I4, respectively, by flexible hinge members generally designated by numeral 20. Said hinge members are best shown in Figures 3 and 4 wherein it will be seen that the same consist of two relatively movable sections, one section being fixedly secured to a stationary support such as the lead-in wire I3, whereas, the other section has fixedly secured thereto a movable electrode or contact member such as I5. A bracket 2| is fixed to the movable electrode I5 and said bracket carries at its free end an armature 22. In a similar manner bracket 23 is fixed to movable electrode I1 and the free end of said bracket carries the armature 24. Said armatures are adapted to be actuated by magnetic means such as 34 and 35 whereby desired movement is imparted to the movable electrodes.

The form of hinge structure as shown in Figures 3 and 4 is described and claimed in my Patent No. 2,442,981 granted June 8, 1948, and relating to Electric Switch Structure. Said member has substantially the shape of the letter H and the same is formed of relatively thin flat spring metal. The elongated spaced legs of the member are each slotted as at 26 and the connecting or transverse central section is cut from slot to slot, as, for example, at 21. Accordingly, the member consists of two sections which are relatively movable and which sections are joined by the outer strip of metal of each elongated leg. The hinge member is further processed to provide said outer strip of metal of each leg with a semi-circular depression 28, each depression or deformation taking such depth and breadth as will draw the severed edges of the connecting central portion toward each other so that the separated parts 30 and 3I of the central portion have overlapping relation, thus providing a fulcrum for the flexing of one section of the hinge member on the other.

In the switch structure as shown in Figures 1 and 2 the flexible hinge members are constructed and arranged to support and resiliently bias the electrodes in opposed directions. In other words, the top electrode I5 is supported and spring tensioned by its hinge member 20 in a downward direction, whereas, electrode I1 is supported by its hinge member 20 and is spring tensioned by the same in an upward direction. A U-shaped member 32 is carried by electrode I5, one leg 01. which is insulated and disposed between electrodes I5 and I1 to thus insulate the electrodes from each other and maintain them in spaced relation against the tensioning of their spring supporting means. The action of the tensioning means on the electrodes in combination with the interposed insulated member 32 will normally locate both electrodes in' an open circuit position with respect to mercury pool II.

Downward movement of both electrodes I5 and II to close their electric circuits through mercury pool II is efiected bythe magnet 34 which is applied to the undersurfaoe of the glass container III so as to influence armature 24 and attract the armature and movable electrode I1 downwardly since movement in this direction is assisted by the spring tension of the top electrode I 5. The spring tensioning of electrodes I5 and I1 is such that electrode II will move downwardly when attracted by magnetic means having the strength of magnet 34 only when it has the assistance of electrode I5. When the second magnet 35 is placed in associated relation with the top surface of tube I0 so as to attract' armature 22 of electrode I5 the effect is toliit'. said electrode I5 thus breaking its circuit withrespect to mercury pool II. However, since magnet 34 remains in an operative position, the lower electrode I1 is retained in contact with the mercury pool so that its circuit is maintained closed. In the event magnet 34 is withdrawn the electrodes of the switch will assume an open circuit position and subsequent return of ,the lower magnet 34 will fail to change the positions of the electrodes for the reason that the spring. assistance of the upper electrode I5 is lacking.

Figure 5 is a schematic wiring diagram illustrating the application of the mercury switch of 7 Figures 1 and 2 to the control system of the invention which is illustrated in connection with an alternating current induction motor having starting and running windings. The lead-in wires I3 and I4 of the mercury switch are electrically connected by means of conductors 31 and 38 with the starting and running windings 40 and 4| of the electric motor generally designated by numeral 42. The other ends of the windings are connected to conductor 43, having electrical connection with one terminal of the electric circuit. An electric resistance element 44 has a series circuit relation with running winding 4I so that the heat generated by the electric resistance element as a result of flow of current through the same will heat the electro-thermal actuator 45 having associated relation with said resistance element. The common terminal, namely I2 of the switch I0, which is in electrical contact with the mercury pool I I has connection by means of the conductor 46 with switch 41 which in turn electrically connects with the other terminal of the electric circuit.

In Figure 5 the parts of the control system are shown in the position which they assume upon closing of switch 41. The magnet 34 has attracted the armature of the bottom electrode I1 and said electrode and also the top electrode I5 has therefore moved downwardly into a circuit closing position with respect to mercury pool I I. The magnet 34.is suitably supported by arm 48 which is pivoted at 50, said arm extending beyond the pivot in a downward direction'and which depending end carries weight 5I, provided with a projecting stop 52. Whereas, magnet 34 is operatively posiassaults tioned by its arm 48 as a result of weight Ii it will be observed that magnet 35 is inoperatively positioned by the action of the electro-thermal actuator 45. Magnet 35 is supported by its arm 53 which is pivoted at 54, the said arm extending beyond the pivot in a downward direction to pro-. vide a depending portion which is engaged by the actuator 45 when the actuator is vertical as a result of an idle .condition of the motor or, in other words, when the actuator is not under the influence of heat generated by resistance element 44. Since both circuits including conductors 31 and 38 are closed upon closing 01' switch 41, the motor 42 starts operating with both startingand running windings energized.

Figure 6 shows the action of the actuator as the motor attains running speed. As a result of the flow or current through the resistance element 44 heat is generated by this element which influences the"actuator,"causing the same to bend or curve in a direction toward the right. Movement of the actuator in this direction releases engagement with the depending leg of arm 53 and thus the permanent magnet 35 is operatively positiond with respect to the switch to attract the armature of the top electrode l5, opening the starting circuit. During normal running of the motor the current through the running winding 4i is decreased in value so as to maintain the electro-thermal actuator 45 in a neutral position, which maintains the parts of the switch in the position as shown in said figure, and the motor continues to run as long as the main switch is closed.

Figure 7 shows the effect of an overload condition on the motor. Should such a condition take place the value of current flowing through the resistance element 44 will increase to such an extent as to cause movement of the actuator 45 to an extreme right hand position where it will engage the stop 52, actuating arm 48, and rendering magnet 34 inoperative. Electrode I! therefore moves upwardly since it is spring tensioned in this direction and the circuit through the running winding of the motor is opened with the resulting stopping of the motor. Figure 8 illustrates the intermediate position of the actuator which it assumes in returning from its extreme right hand position, as shown in Figure 7, to its upright position as shown in Figure 5. It will be observed in Figure 8 that although magnet 34 is restored to operative position the motor circuits are not closed through the switch due to the fact 'that the necessary cooperative action of the top electrode I5 is lacking since said top electrode is under the influence of the upper magnet 35. When the upper magnet 35 is rendered inoperative by the actuator assuming a vertical position, both electrodes will move downwardly into a circuit closin'g position under the influence of theoperatively positioned lower magnet 34. A restarting of the motor is initiated asldescribed with respect to Figure 5 and wherein both starting and running windings of the motor are energized.

The foregoing motor control arrangement provides for a restart after a delay. Such an arrangement, particularly in connection with electric household refrigerators, is desirable since many of the causes of overload are self-corrective and delays between restarting generally provide a time element during which said overload causes may be removed, whereupon normal operation may be resumed. In any event, the motor control arrangement of the invention will not permit such overload causes as are not self or time-corrective to be injurious to the motor because of the short runs and subsequent idle periods of operation.

Figures 9 and 10 show a modified arrangement employing mechanical interlock means for controlling certain movements of the permanentforce of the magnet is self-sufficient to bring about switch operation. The circuit diagram shown in Figure 9 is similar to that shown in Figure 5 and the permanent magnets 34 and 35 are carried by their respective arms and 53 pivoted at 50 and 54. The depending leg of arm v 48 carries the weight 5| and the stop 52, and the electro-thermal actuator 45 is adapted to engage the depending leg of arm 53 when in vertical position, as previously described in connection'with Figure 5.

The interlock comprises a pivoted latch 55,1neluding a hook 56 at its lower depending end and which latch is adapted to be engaged by an arm 51 forming part of and extending outwardly from arm 53. In Figure 9 the latch has been rotated to remove hook 56 from engagement with part 58 fixed to arm 48, the said position being attained as a result of the electro-thermal actuator 45 contacting the depending leg of arm 53 and the movement imparted thereto being transmitted through 51 to the latch. The magnet 35 thus assumes an inoperative position; latch 55 is released with respect to arm 48 so that magnet 34 is operatively positioned, and the electrodes of the switch move into circuit closing position to start operation of motor 42 with both windings, namely, the starting winding 40 and the running windin 4| being energized.

As the control apparatus above described assumes a running position, brought about by the warping of the actuator 45 in a manner as prev viously described, the upper magnet 35 will assume an operative position and the latch 55 will be rotated in a clockwise direction since the force applied thereto by 51 is removed. As a result hook 56 moves to an associated position with respect to 58. In the event of an overload condition developing the actuator 45 will be caused to move to an extreme right hand position, as best shown in Figure 10. In this position contact is made with stop 52 and the arm 48 is actuated to withdraw magnet 34, rendering the same inoperative. As a result of this action hook 56 is caused to engage part 58 and said latch is thus operative to hold the arm in this position with magnet 34 withdrawn. This constitutes a locked-out position of said lower magnet and the parts remain as shown in Figure 10 until actuator 45 has cooled suiliciently to assume a vertical position where contact with the depending leg of arm 53 moves magnet 35 to an inoperative position. Simultaneously with movement of magnet 35 to an inoperative position arm 51 will be caused to rotate latch 55 counterclockwise, withdrawing hook 53 from part 58, thus permitting magnet 34 to again become operative. Said lower magnet produces operation of the switch, resulting in a closing of both circuits including the starting and running windings and the motor resumes operation.

Since the switch'structure 0!. Figures 9 and 10 is not dependent upon the spring tensioning 'of the electrodes to bring about the desired sestructures, for, in this modification, the opera tion of one electrode is not, of itself, dependent. Figure 11 illustrates a modification of the control system coming within the invention and which includes an actuator for the magnets responsive to temperature in combination with a temperature or pressure responsive'device for additionally controlling one of the magnets. In this form of the invention the resistance element 44a is located in proximity to the thermal actuator 45 and said resistance element ,is energized in accordance with the current of the operating motor of the apparatus, such as a refrigerator, to which the control system may be applied. In this modification the actuator operates arm 53 and magnet 35 in the, same manner as described with respect to Figures to 8 inclusive. Arm 48 and magnet 34 are also operated by the actuator in the event of an overload or stalled condition of the motor devel oping as described, but in this modification the armiis additionally controlled by a second condition responsive device in the form of aBourdon tube identified by numeral 60. The bracket 6| connected to the tube at its end provides the pivot 52 for pivotally supporting the lever 53.

Said lever at its right hand end has bearing contact with the top surface of arm 48 and at its left end said lever carries the adjusting screw 84 which engages the eccentric 55 providing for adjustment of the lever whereby the position of arm 43 with respect to the switch may be varied to require more or less movement of the Bourdon tube in order to bring about the closure of the circuits through the switch and thus predetermine the condition affecting operation of the magnet 34.

The tube 50 may be temperature or pressure actuated. Upon expansion of the tube the lever- 63 is caused to release arm 48 and thus magnet 34, allowing the magnet to become operative, as a result of an increase in temperature produced within the refrigerating compartment, thus increasing the temperature of a sealed volatile liquid charged system including the Bourdon tube. Thus the actuator 45 provides a starting control for the refrigerating apparatus together with a safety control in the event of an overload on the motor, whereas, tube 60 will control operation of the apparatus in response to certain predetermined conditions.

In Figure 12 the control system of the invention has been applied to an electrically operated oil burner heating system with control being provided for the oil burner motor and ignition. The conductors 31 and 38 electrically connect with the electrodes l5 and ll of the switch, and it will be seen that conductor 31 directly connects with one terminal of an ignition transformer 61. Conductor 38 electrically connects with the resistance element 44b having encircling relation with the actuator 45, the resistance element being connected in turn to one terminal of the electric motor 68 of the oil burner. Con.- ductor 69 connects the second terminal of the oil burner motor with the second terminal of ignition transformer 51. The conductor 10 electrically connecting with contact I2 of the switch connects the switch to terminal Li, having electrical connection with one side of the electrical supply source, while terminal L2 connects the other side of said source to the motor and ignition transformer by means of conductor 13 hav- 5 ing electrical connection with conductor 53. Thus with the closure of the switch electrodes l5 and II the motor and ignition transformer may be energized. The secondary circuit of the ignition transformer provides the ignition for the oil burner in the form of a spark gap identifled by numeral 13.

The terminals of a stationary primary winding ll of a transformer are respectively connected to the terminals L1 and L2. The secondary winding 12 of the transformer is electrically connected by conductors 14 and 15 to the room thermostat 16, the circuit including the secondary winding being closed when the room thermostat is closed. The secondary o winding of the transformer is movable upon one leg of the transformer core so that upon closing the thermostat circuit the winding will be repelled to move upwardly. Carried by the secondary winding is an operator 11 arranged for engagement with arm 48 to control the position of magnet 34. Magnet 35 is carried by arm 53 and both said arms are also controlled by the thermal-actuator 45in a manner as de-' scribed with respect to Figures 1 to 8 inclusive. 3" The control circuit of Figure 12 provides burner motor and ignition energization with subsequent cut-off of the ignition means and is operative to prevent operation of the burner motor without a closure of the ignition circuit when starting the burner after a period of idleness. It will be observed that the room thermostat 16 must first close in order to start operation of the oil burner system since normally the secondary winding 12 will maintain magnet 34 inoperative. When-the room thermostat I6 closes the secondary winding 12 is energized to efiect upward movement of operator I1 and magnet 34 is rendered operative to attract electrodes i5 and H which thus movedownwardly into a closed circuit position. The oil burner motor GB is energized as is also the ignition transformer 67 so that operation of the motor takes place simultaneously with operation of ignition 18. Subsequent cut-off of the ignition is effected by the thermal-actuator 45 which is caused to warp slightly in a right hand direction as a result of the heat generated by resistance element 44b. Release of arm 53, due to this warping action of the actuator, renders magnet 35 operative and electrode 15 is attracted, breaking the circuit to ignition transformer 51. The oil burner motor 68, however, continues in operation unless an overload condition develops, in which event the thermal-actuator operates as a safety control contacting weight 5| and rendering magnet 34' inoperative, all in a manner as previously described. In the event motor 68 is operating satisfactorily the same continues in operation until the room thermostat l6 breaks contact to .open the circuit to the secondary winding 12, thus deenergizing the winding. With the winding deenergized it will descend to a normal position with operator 1'|, rendering magnet 34 inoperative, and electrode II will move to an open circuit position, thus opening the circuit to the oil burner motor 63. When the motor circuit is broken by withdrawing of magnet 34 'r'rom operative position by de-energization of the transformer circuit for any reason, a subsequent re-energization and return of magnet 34 to operative position will not fasaaaso result in restarting the burner motor unless or-- untilthe influence of magnet 35 has been resimultaneously establish a circuit to the ignition transformer with the closure of the motor circui Supplementing the motor and ignition control as represented by Figure 12 may be one of several forms of combustion or iiame responsive mechanisms, commercially available, which may be employed to cooperatively function with the device for control of magnet 34 whereby operation of the burner may be controlled to prevent continued operation of the burner in the event of ignition or name failure. While permanent magnets are shown in the illustrated embodiment of this invention, electro-magnets may be used. As for'example, with reference to Figure 12, the magnet 34 may take the form of an electromagnet rendered operable by the thermostat I6 thus eliminating the transformer actuated operator as shown.

The invention is not to be limited to or by details of construction of the particular embodiment thereof illustrated by the drawings, as various other forms of the device will of course be apparent to those skilled in the art without departing from the spirit of the inventibn or the scope of the claims.

What is claimed is: l. A multiple circuit controlling device comprising circuit control means having a first and second electrode movable to and from closed circuit positions and electrically connected to separate circuits to becontrolled, means spring tensioning the first electrode toward closed position,

and against the second electrode to an extent whereby they normally assume an open position, a magnet operatively effective to cause the second electrodeto close provided it is assisted in said movement by the spring tensioning of the first electrode, whereby both electrodes move to a closed circuit position, said magnet being effective to hold the second electrode in a closed positheir respective electrodes through the walls thereof. 4. A multiple circuit controlling device comprising circuit control means having a pair of electrodes movable to and from closed and open positions and electricallyconnected to separate circuits to be controlled, magnetic means for each electrode for controlling actuation of the electrodes, a plurality of automatic means for rendering-said magnetic means operative, one of said automatic means effecting such operation of the magnetic-means as to cause both electrodes to move to a closed circuit position and to cause said electrodes to open selectively whereby said circuits are opened in sequence, the other of said automatic means being independently operative in one position to permit the closure of the switch circuits by the first automatic means and independently operative in a second position to prevent the closure of said switch circuits.

5. A multiple circuit controlling device comprising circuit control means having a pair of electrodes movable to and from closed and open positions and electrically connected to separate circuits to be controlled, a first magnet for actuating an electrode included in a first circuit to be controlled, a pivoted arm supporting said first magnet in normal operative position. a second magnet for actuating the electrode included in a seeond circuit to be controlled, a second pivoted arm supporting said second magnet in normal operative position, automatic means adapted to actuate the arms individually to render their retion without the assistance of the spring tensioning of the first electrode, another magnet operatively eil'ective on the first electrode only, to cause said electrode to assume an open circuit position, and automatic condition responsive means for operating the magnets to render them operatively effective upon their respective electrodes.

2. A multiple circuit controlling deviEe as defined by claim 1, wherein both magnets are movable and normally adapted to assume an operative position with respect to their respective electrodes, and wherein said automatic condition responsive means comprises temperature responsive means operating in one position to position the first magnet in inoperative position and in another position to position the second magnet in inoperative position, and additionally including other automatic means independently operative in one position to permit the second magnet to assume its normal operative position, and independently operative in a second position to render said magnet inoperative.

3. A multiple circuit controlling device as defined by claim 1, wherein the movable electrodes are sealed within a non-magnetic container, a body of mercury contained therein to be engaged by the movable electrodes to establish a closed circuit, and wherein said magnets are arranged for operation adjacent the container to actuate spective magnets inoperative, and latching means for holding the second pivoted arm in an inoperative position, said latching means being rendered operative by the first mentioned arm when said first magnet is operatively positioned.

6. A multiple circuit controlling device comprising circuit control means having a first and second electrode movable to and from closed and open positions and electrically connected to separate circuits to be controlled, a'flrst magnet operative upon the first electrode to actuate the same from a closed position to an open position, a second magnet operative upon the second electrode to actuate said electrode from an open, position to a closed position, and condition responsive means for selectively actuating the magnets, said means having a first actuating position in which the first magnet is rendered inoperative and the second magnet operative. an intermediate nonactuating position in which both magnets are r ndered operative, and a third actuating position in which the second magnet is rendered inoperative and the first magnet operative, and means operative when said first magnet is operati e to maintain said second magnet inoperative when rendered inoperative by the condition responsive means.

'7. A multiple circuit controlling device compri ing circuit control means having a pair of electrodes movable to and from closed and open positions and electrically connected to separate circuits to be controlled, independent magnetic means for actuating each of said electrodes. automatic means having operation to condition the magnetic means by rendering them operative or inoperative, said automatic means sequentially condit oning said magnetic means in response to a condition produced when the controlled circu ts are closed and energized so that the magnet c means actuate t eir re pective electrodes to effect an open circuit position of the same, said automatic means also sequentially conditioning said magnetic means in response to another condition produced when both controlled circuits are open so that the magnetic means actuate their respective electrodes to effect a closed circuit position of the same, and other means operative when both electrodes have moved to open circuit posiwith respect to a body of mercury also located within said container, magnetic means for actuating each of said electrodes, said magnetic means each being located exteriorlv of the container and being independently movable between operative and inoperative positions to vary the effectiveness of the magnetic field upon its respective electrode so as to actuate the same, automatic means having operation to condition the said magnetic means by rendering them operative or ino erative, said automatic means sequentially conditioning the magnetic means in response to a condition produced when the controlled circuits are closed and energized so that the magnetic means actuate their respective electrodes to effect an open circuit position of the same, and said automatic means also sequentially conditioning said ma netic means in response to another condition produced when the controlled circuits are open so that the magnetic means actuate their respective electrodes to effect a closed circuit position of the same.

9. A multi le circuitcontrolling device as defined by claim 8, additionally including other means operative when both electrodes have moved to open circuit position to prevent the reclosing of either circuit through its respective electrode, until said automatic means conditions both of said magnetic means to render the magnetic means operative to close'both electrodes simultaneously.

10. A multiple circuit controlling device comprising circuit control means having a pair of electrodes movable to and from closed and open positions and electrically connected to separate circuits to be controlled, a first magnetic member for actuating one of said electrodes and a second magnetic member for actuating the other of said electrodes, automatic means having operation to condition both said magnetic members by rendering them operative or inoperative, said automatic means having a start position wherein the first magnetic member is rendered inoperative and the second magnetic member is rendered operative as regards their respective electrode whereby to actuate both electrodes into closed circuit positions, said automatic means sequentially conditioning said magnetic members in response to a condition produced when the controlled circuits are closed and energized so that the magnetic members actuate their respective electrodes to effect an open circuit position of the same, and said automatic means sequentially conditioning said magnetic members in response to another condition produced when both controlled circuits are open so that the magnetic members actuate their respective electrodes to effect a closed circuit position of the same.

11. A multiple circuit controlling device as cisl2 flnedby claim 10, additionally including other means operative when both electrodes have moved to open circuit position to prevent the reclosing of either circuit through its respective electrode,

until said automatic means conditions both said magnetic members to render the magnetic members operative to closeboth electrodes simultaneously.

12. A multiple circuit controlling device comprising a pair of electrodes hermetically sealed within a non-magnetic container, electrically connected to separate circuits to be controlled and movable to and from open and closed positions with respect to a body of mercury also located within said container, a first magnetic member for actuating one of said electrodes and a second magnetic member for actuating the other of said electrodes, said magnetic members being located exteriorly of the container and being independently movable between operative and inoperative p0- sitions whereby to vary the effectiveness of their magnetic neld upon their respective electrode so as to actuate the same, automatic means having operation to condition both said magnetic members by rendering them operative or inoperative, said automatic means having a start position wherein the first magnetic member is inoperatively positioned and the second magnetic member is operatively positioned as regards their respective electrode whereby to actuate both electrodes into closed circuit positions, said automatic means sequentially conditioning said magnetic members in response to a condition produced when the controlled circuits are closed and energized so that the magnetic members actuate their respective electrodes to effect an open circuit position of the same, and said automatic means sequentially conditioning said magnetic members in response to another condition produced when both controlled circuits are open so that the magnetic members actuate their respective electrodes to effect a closed circuit position of the same.

13. A multiple circuit controlling device comprisin a pair of electrodes hermetically sealed within a non-magnetic container, electrically connected to Separate circuits to be controlled and movable to and from open and closed positions with respect to a body of mercury also located within said container, a first magnetic member for actuating one of said electrodes and a second magnetic member for actuating the other of said electrodes, said magnetic members being located exteriorly of the container and being independently movable between operative and inoperative positions whereby to vary the effectiveness of the magnetic field upon their respective electrode so as to actuate the same, automatic means having operation to condition both said magnetic members by rendering them operative or inoperative, said automatic means sequentially conditioning said magnetic members in response to a condition produced when the controlled circuits are closed and energized so that the magnetic members actuate their respective electrodes to effect an open circuit position of the same, said automatic means also sequentially conditioning said magnetic members in response to another condition produced when both controlled circuits are open so that the magnetic members actuate their respective electrodes to eifect a'closed circuit position of the same, and other means operative when both electrodes are moved to open circuit position to prevent the reclosing of either circuit through its respective electrode, until said automatic means conditions both said magnetic members by rendering the second magnetic member operative and. the first magnetic member inoperative as regards their respective electrode whereby the magnetic members effect the closing of both electrodes simultaneously.

14. A multiple circuit controlling device comprising a top electrode and a bottom electrode hermetically sealed within a non-magnetic container and movable to and from open and closed positions with respect to a body of mercury also located within said container, a first magnetic member located exteriorly of the container for actuating the top electrode, a second magnetic member also located exteriorly of the container for actuating the bottom electrode, a first pivotedarm supporting the first magnetic member in normal operative position for attracting its electrode, a second pivoted arm supporting the second magnetic member in normal operative position for attracting its electrode, automatic condition responsive means adapted to actuate the arms individually to render their respective magnetic members inoperative, and latching means for holding the second pivoted arm in an inoperative position, said latching means being rendered operative by the first pivoted arm when the first magnetic member is operatively positioned.

15. A multiple circuit controlling device as defined by claim 14, wherein said condition responsive means has a start position in which the first pivoted arm is actuated rendering the first magnetic member inoperative, a running position in which neither arm is actuated so that the magnetic members assume their normal operative position, and an overload position in which the second pivoted arm is actuated to render the second magnetic member inoperative.

IRA E. McCABE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

